Apparatus for reducing the thickness of metal

ABSTRACT

Apparatus for reducing thickness of metal having a pair of oscillatable arms having workrolls on adjacent free ends one on each side of a passline for metal, each arm being pivotable between spaced-apart supporting beams which are interengaged by a shaft which allows for limited angular movement of one beam relative to the other when a load safety device of one beam fails so as to ensure failure of the load safety device of the other beam.

United: States Patent I 91 Saxl [ Jan. 23, 1973 1 APPARATUS FOR REDUCING THE THICKNESS OF METAL [7 5 Inventor: I fiifskij Sutton, Coldfie ldiwarwickshire, England [73] Assignee: Imperial Metal Industries (Kynoch) Ltd., Witton Birmingham. England [22] Filed: Oct. 26, 1971 [2]] Appl. No.: 192,159

[30] Foreign Application Priority Data Nov. 9, 1970 Great Britain ..53,l22/70 [52] [1.8. CI. ..72/1, 72/237, 72/465 [51] Int. Cl. ..B2lb 33/00 [58] Field of Search ..72/1, 3,4, 5,237,465;

[56] V 7' References Cited UNITED STATES PATENTS 3,055,243 9/1962 Cauley et al ..72/4

Primary ExaminerLowell A. Larson Attorney-Cushman, Darby & Cushman [57] ABSTRACT Apparatus for reducing thickness of metal having a pair of oscillatable arms having workrolls on adjacent free ends one on each side of a passline for metal, each arm being pivotable between spaced-apart supporting beams which are interengaged by a shaft which allows for limited angular movement of one beam relative to the other when a load safety device of one beam fails so as to ensure failure of the load safety device of the other beam.

7 Claims, 4 Drawing Figures PATENTEDJAMZB ms 3,712,092

sum 2 [IF 4 APPARATUS FOR REDUCING THE THICKNESS OF METAL BACKGROUND OF THE INVENTION This invention relates to apparatus for reducing the thickness of metal of the kind in which a pair of arms are oscillatable each about a pivotal axis upon a pair of face-to-face and parallel spaced-apart supporting beams, each pair of beams being pivotally movable about an axis spaced from the pivotal axis of its arm, and the arms having freely rotatable workrolls mounted upon their free ends which lie closer together than their pivotal axes, and in which driving means is provided so as to effect oscillation of the arms in synchronism with each other. This apparatus will be referred to throughout this specification as apparatus of the kind described.

Each beam is pivotally mounted at one end to a frame of the apparatus and at the other end a co'mponent of rolling load acts through a screw down loadcarrying mechanism which is adjustable so as to alter the pivotal position of the beam thereby to adjust the workroll gap between the workrolls and to equalize the workroll gap along the length of the rolls.

Screw-down mechanisms are thus provided at each end of the rolls. It has been found desirable to incorporate in each screw-down mechanism a load safety device which comprises a load safety member intended to break in use if a working load, eg a roll separating force applied to it exceeds a predetermined maximum value.

However, failure of a load safety device at one end of a workroll results in separation of the workrolls at that end of the rolls and consequently the rolls tilt with respect to each other and impose undue strain on other parts of the apparatus.

Furthermore, the load safety device at the other end of the workroll and which did not fail will be subjected to a smaller load as a result of the non-parallel opening of the rolls making it less likely to fail.

An object of the present invention is to provide a construction in which failure of one device at one end of a workroll will be rapidly followed by failure of the device at the other end of the workroll thereby restricting relative tilting of the workrolls to an acceptable level.

SUMMARY OF THE INVENTION According to the present invention, in apparatus of the kind described, a screw-down mechanism operates on each beam and each mechanism incorporates a load safety device, the beams of at least one pair of beams being interengaged by shaft means, the shaft means permitting limited rotational movement of the beams relative to one another below'a predetermined torque but maintaining the angular relationship of the two beams at or in excess of said'torque whereby a turning moment induced in one beam upon failure of the load safety device of its screw-down mechanism will be transmitted to the other beam of the pair and result in failure of the load safety device of the other screwdown mechanism.

The shaft means may comprise a single pivotal shaft interconnecting the two beams and which will twist below the predetermined torque but which at this torque will maintain the angular relationship of the two beams.

Alternatively, and preferably the two beams are not interconnected by the shaft means but the shaft means incorporates interengageable abutment means which permit limited relative rotation of the two beams. The abutment means may comprise a tongue associated with one beam of each pair and a recess associated with the other beam. In this case one part of the abutment means may be on one beam and another part on a shaft which extends from the other beam. It is preferable, however, that the shaft means comprises two co-axial pivotal shafts rigidly connected to and extending one from each beam towards the other beam, and the abutment means are on the two shafts.

Conveniently the abutment means comprises a diametral tongue on the end of one shaft and a diametral recess in the end of the other shaft freely to receive said tongue. Preferably the abutment means comprises adjustment means whereby the permitted relative rotation of the two shafts may be varied. The adjustment means may comprise stop pins screwthreadably engaged in said other shaft and projecting into the recess normal to the sides of the recess.

BRIEF DESCRIPTION OF THE DRAWING One embodiment of the invention will now be described by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic side elevational view of apparatus for reducing the thickness of metal;

FIG. 2 is a side elevational view, partly in cross-section of part of the apparatus of FIG. 1;

FIG. 3 is a view partly in cross-section of part of the apparatus of FIG. 2 and on a larger scale than shown in FIG. 2, and

FIG. 4 is a view along line IV-IV of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the embodiment, apparatus for reducing the thickness of metal consists of a rolling mill which is basically of similar construction to apparatus for reducing metal thickness as described in the specification of our U.S. Pat. No. 889,662.

The mill basically comprises a pair of pendulum arms 1 and 2, each pivotally mounted between a pair of arm carrying beams 3 of the millabout a pivotal axis 4 located intermediate the beam ends. One beam 3 of the upper pair only is shown in FIG. 2. The two axes of the two arms are disposed one directly above the other. A part of each arm extends from its pivotal axis towards the other arm to terminate in an end of the arm opposing that of the other arm. Each of the opposing ends is provided with a workroll 5 freely rotatably mounted therein with its axis parallel to the pivotal axis, and a plurality of back-up or supporting rolls 6 for the workroll. The arms oscillate about their axes on both sides of a pass line AA to move the workrolls in synchronism alternately in the direction of advance of the metal and then in the opposite direction with the axes of the workrolls extending in a direction normal to the pass line. Driving means is provided for oscillating each arm, the driving means comprising a crank rod 7 pivotally mounted at one end 8 to the arm and at its other end to a crankshaft 9 which is drivable by a drive motor and gearing (not shown).

During use of the mill to reduce the thickness of metal (FIG. 1), as the arms oscillate, the metal exerts a rolling load upon the workrolls. A component of the rolling load acts along the arms and this component fluctuates during each oscillation of the arms, and the magnitude of the component of rolling load at any instant is dependent partly upon the direction of movement of the arms at that instant and partly upon their angular position relative to the pass line of the metal.

The fluctuating component of load in each arm is taken through the associated beams 3 of the arm into the mill frame 11 and for this purpose, beams of each pair are pivotally mounted, at one end, about a common axis 3a to the mill frame, and the other end of each beam is free and is operably engaged by a screw-down load mechanism 12 through which the fluctuating rolling load component is to be transmitted. As all the mechanisms are similar only an upper mechanism will now be described.

As shown in FIG. 3, each screw-down load mechanism 12 comprises a male screw-threaded member 13 for adjustable movement relative to the frame to vary the minimum gap between the workrolls. The screw-threaded member extends towards the free end of its associated beam and an end of the member located adjacent the beam is surrounded by a tubular portion of a member 14. A lower end of member 14 is provided with a blind axially extending bore 15 within which is slidably received a load safety device 16.

In respect of each screw-down mechanism, the load safety device comprises one load carrying member in the form of a cup-shaped housing 17 slidable within the bore 15 with a base of the housing projecting from the bore. A recess 18 in the outer radial surface of the base of the housing receives the base of a beam-contacting member 19. The beam-contacting member projects from the recess and the projecting portion has a semicircular surface 20, considered in cross-section, which is seated within an arcuate seat 21 provided at the free end of its beam to allow for angular movement between the beam and beam-contacting member during adjustment of the screw-down mechanism. Within the base of the housing is contained a load safety member 22. This load safety member is a flat metal plate in the form of an annulus. The radially outer regions of the lower surface of each load safety member are supported by an annular abutment surface 23 of its housing 17, the abutment surface being spaced, for instance, by 0.15 inch from an end surface 24 within the base of its cupshaped housing. A relatively thin padding washer 25 of relatively soft metal is located between the member 22 and surface 23 to prevent indentation of the member by the edge of the surface.

The device further comprises a second load carrying member which is a metal plug 26 disposed coaxially within the cup-shaped housing by means of a distance piece 27 spacing the plug from the inner wall of the housing. The plug has an upper end which projects from the housing and lies in engagement with a raised surface 28 provided at the base of the blind axially extending bore 15 of the screw-threaded member of the associated screw-down mechanism. A lower end 29 of the plug has an annular abutment surface which engages a part of the upper surface of the member 22. As may be seen from FIG. 3, the parts of the upper and lower surfaces of member 22 which are engaged by the plug and the housing are spaced apart in the plane of the member so that if the plug is urged downwardly, member 22 is loaded in bending and in shear. It will be appreciated that this will increase the resilience of the member 22 beyond that which it would have solely in shear and so as ultimately to decrease the tendency of fatigue. The member 22 is designed to break in bending and in shear if a load applied to it between housing and plug reaches a value above that normally applied to the member but below that which would cause damage to other parts of the mill. The two load safety members of the upper beams are designed to break at a load slightly less than the ones of the lower beams so that breakage of the upper and lower members occurs at different stages during the application of excessive load.

Upper and lower portions of the plug define between them an annular abutment shoulder 30 engaging a retaining means to hold the plug in a position urged downwardly so as to preload the member 22 in bending and shear. This means comprises an adjusting nut 31 which is screw-threadably received within a screwthreaded portion 32 of the cup-shaped housing.

Before assembly of each device 16 into the mill, the member 22 is preloaded to a predetermined value by placing the device in a compression machine to force the plug onto the member to subject it to shear and bending stress.

The adjusting nut 31 is then screw-threadably adjusted so as to hold the plug and housing in their respective positions set by the compression machine so as to maintain the preload on the member 22. The preload which is applied to each member 22 is between the normal maximum load applied to the member and the designed breaking load of the member.

Each pair of beams are interconnected along their common pivotal axis 3a by shaft means 33 (FIG. 4) in the form of coaxial pivotal shafts 34,35. The shaft 34 is integrally formed with one beam 3 and extends from the beam towards the opposing beam 3b. The free and portion of the shaft 34 is provided with a diametral recess 36 which has a length greater than the diameter of the shaft by virtue of channel-shaped projections 37 on opposite sides of the shaft. The projections 37 provide opposed side walls 38 in which screw-threaded pins 39 are screw-threadably engaged so that the pins can project into the recess 36 normal to the sides of the recess. Locknuts 40 are provided on the pins 39 for setting the amount of projection of the pins into the recess 36. Four pins 39 are provided, two at each side of the shaft 34.

The free end portion of the shaft 35 is integrally formed with the beam 3!) and extends from the beam 3b towards the opposing beam 3. The free end portion of the shaft 35 is provided with a diametral tongue 41 which projects from the end of the shaft. The tongue has a thickness less than the width of the recess 36 and a length substantially equal to the length of the recess 36 so that the tongue is freely receivable in the recess 36 and between the pins 39.

In use of the mill, the pins 39 are adjusted to provide the permissible degree of relative rotation of the two shafts 34 and 35 beyond which the two shafts will rotate as a single unit by virtue of the pins 39 engaging with the tongue 41.

Reverting to the load safety mechanism, during use of the mill, as metal is being reduced in thickness by movement between the workrolls 5, a fluctuating component of rolling load is carried through the free end of each beam 3, through the beam contacting member into the base of the cup-shaped housing 17 and from there through the preloaded load safety member 22 (in the same sense and direction as the preload) and to plug 26 and into the screw-threaded member 13 of the screw-down mechanism. When the component of load is being applied normally, i.e. below the preloaded value of each load safety member, it is found that the load exerted upon the load safety member does not fluctuate or fluctuates with amplitudes which are insignificantly small compared with those of the component of rolling load. This is because the fluctuating component of rolling load substantially does not add to the preload, but in contrast has the effect of lessening the preload as the value of the component of rolling load increases so that the sum of the lessened preload and the rolling load component equals the preset preload figure. The lessening effect of the preload is caused because the component of rolling load acting upon the housing 17 relieves the pressure of the adjusting nut 31 upon the shoulder of the plug. During normal use of the mill, therefore, while the fluctuating component of rolling load does not exceed the preload condition, each load safety member will not be subject to fatigue conditions.

If, for any reason, the component of rolling load exceeds the preload, then the shear and bending load on each load safety member 22 will increase and will result in shear breakage of at least the upper members if the component of rolling load exceeds the designed breaking load of the member. in this event, in the upper load safety mechanisms, the plugs 26 break the load safety members by sliding movement of the cup-shaped housings towards the bases of the bores of the screwthreaded members, this movement being stopped after movement of 0.15 inch when the sheared portions of the load safety members engage the end surfaces 24 within the base of the housings. If this movement does not effect reduction in the component of load, then the lower load safety members are sheared after which the rolling load is substantially reduced.

However, failure of these load safety members in only one of the load safety devices results in separation of the workrolls at that end of the rolls and the rolls tilt with respect to one another. This causes one of the pair of beams 3, 3b to rotate about the pivotal axis 3a relative to the other of the pair. This relative rotation of the two beams is limited by the present invention and, in the present embodiment, the relative rotation is limited by the tongue 41 of the shaft 35 abutting the ends of the pins 39. Consequently, if we assume that the load safety device associated with beam 3 has failed, then beam 3 will rotate about its pivotal axis 3a relative to beam 3b.

When the relative movement has reached the limit allowed by the clearance between the pins 36 and the tongue 41, the torque imposed in the beam 3 by the overload is transmitted to the beam 3b thereby increasing the load carried by the load safety device associated with beam 3b. This increased load will cause the safety device of beam 317 to fail in rapid succession to that of the beam 3 whereby relative tilting of the rolls will be minimized.

Iclaim:

1. Apparatus for reducing the thickness of metal comprising a pair of arms, a pair of face-to-face and parallel spaced-apart beams for each arm, each arm being pivotally mounted about a pivotal axis upon its pair of beams which are pivotally movable about an axis spaced from the pivotal axis of the arm, the arms having free ends which lie closer together than their pivotal axes and having freely rotatable workrolls mounted upon their free ends, a screw-down mechanism operating on each beam, each screw-down mechanism incorporating a load safety device and driving means to effect oscillation of the arms in synchronism with each other wherein in the improvement a shaft means is provided which interengages the beams of each pair of beams, the shaft permitting limited rotational movement of the beams of its associated pair relative to one another below a predetermined torque applied to the shaft and operating to maintain the angular relationship of the two beams when the predetermined torque on the shaft is exceeded to transmit a turning moment from one beam to the other beam upon failure of one load safety device to result in failure of the other load safety device.

2. Apparatus according to claim 1 wherein the shaft means for each pair of beams incorporates interengageable abutment means which permit limited relative rotation of the two beams.

3. Apparatus according to claim 2 wherein the abutment means comprises a tongue associated with one beam of each pair and a recess associated with the other beam, the recess receiving the tongue.

4. Apparatus according to claim 2 wherein there are two coaxial pivotal shafts connected to and extending one from each beam towards the other beam, and the abutment means are on the two shafts and allow a limited relative rotation of the two shafts.

5. Apparatus according to claim 4 wherein the abutment means comprises a diametral tongue on the end of one shaft and a diametral recess in the end of the other shaft which receives the tongue.

6. Apparatus according to claim 5 wherein adjustment means is provided whereby the permitted relative rotation of the two beams may be varied.

7. Apparatus according to claim 6 wherein the adjustment means comprises at least one stop pin screwthreadably engaged in one of the shafts so as to project into the recess and engage the tongue. 

1. Apparatus for reducing the thickness of metal comprising a pair of arms, a pair of face-to-face and parallel spaced-apart beams for each arm, each arm being pivotally mounted about a pivotal axis upon its pair of beams which are pivotally movable about an axis spaced from the pivotal axis of the arm, the arms having free ends which lie closer together than their pivotal axes and having freely rotatable workrolls mounted upon their free ends, a screw-down mechanism operating on each beam, each screw-down mechanism incorporating a load safety device and driving means to effect oscillation of the arms in synchronism with each other wherein in the improvement a shaft means is provided which interengages the beams of each pair of beams, the shaft permitting limited rotational movement of the beams of its associated pair relative to one another below a predetermined torque applied to the shaft and operating to maintain the angular relationship of the two beams when the predetermined torque on the shaft is exceeded to transmit a turning moment from one beam to the other beam upon failure of one load safety device to result in failure of the other load safety device.
 2. Apparatus according to claim 1 wherein the shaft means for each pair of beams incorporates interengageable abutment means which permit limited relative rotation of the two beams.
 3. Apparatus according to claim 2 wherein the abutment means comprises a tongue associated with one beam of each pair and a recess associated with the other beam, the recess receiving the tongue.
 4. Apparatus according to claim 2 wherein there are two coaxial pivotal shafts connected to and extending one from each beam towards the other beam, and the abutment means are on the two shafts and allow a limited relative rotation of the two shafts.
 5. Apparatus according to claim 4 wherein the abutment means comprises a diametral tongue on the end of one shaft and a diametral recess in the end of the other shaft which receives the tongue.
 6. Apparatus according to claim 5 wherein adjustment means is provided whereby the permitted relative rotation of the two beams may be varied.
 7. Apparatus according to claim 6 wherein the adjustment means comprises at least one stop pin screw-threadably engaged in one of the shafts so as to project into the recess and engage the tongue. 